Avaliação comparativa do valor prognóstico de quatro marcadores bioquímicos de lesão miocárdica pós intervenções percutâneas utilizando stents coronarianos

Abstract

The systematic assessment of total creatine kinase (total CK) and its MB subfraction (CK-MB) after percutaneous coronary intervention shows that 5% to 40% of the patients successfully treated have an elevation in the serum level of those enzymes, which may represent a certain degree of myocardial necrosis [1][2][3] . Recently, the analysis of other very sensitive biochemical markers specific for identifying myocardial damage (CK-MB mass, troponins T and I) has intensified the detection of that phenomenon, which has been much more frequently observed with the implantation of coronary stents 4,5 .This study aimed at establishing the clinical meaning of those alterations and their impact on the occurrence of adverse cardiac events. It also had the following objectives: 1) to assess the incidence of the elevations in the CK-MB activity and mass and in the levels of troponins T and I after elective coronary stenting; 2) to analyze the association between the elevation of the markers and clinical, angiographic, and technical variables, and periprocedure problems; 3) to determine the prognostic effect of the elevation of the 4 markers after intervention on the occurrence of death, myocardial infarction, and need for new revascularization procedures in a one-year period. MethodsThis prospective study comprised 199 consecutive patients from the coronary angioplasty unit at the Instituto Dante Pazzanese de Cardiologia. They underwent elective coronary stent implantation for the treatment of stenoses located in native coronary arteries from August 2001 to January 2002. The patients met the following inclusion criteria: both genders; no restriction regarding age; normal levels of CK-MB activity in the 24 hours preceding the intervention; patients with clinically controlled stable or unstable angina (no recurrence of pain in the 2 weeks preceding the percutaneous treatment, to reduce the chances of an elevation in the troponins before the procedure); asymptomatic patients with ischemia detected on functional tests; presence of luminal obstruction > 50% in one or more vessels, with primary lesions anatomically favorable to stent implantation; absence of severe left ventricular dysfunction (EF > 0.30); elective treatment with angiographic success at the end of the procedure.The exclusion criteria were as follows: renal failure (creatinine > 2.0 mg/dL); presence of comorbidities that could affect late ResultsChanges in the levels of the 4 markers after stent implantation are relatively frequent (6.1% to 32.8%) ConclusionSystematic monitoring of CK-MB activity after coronary stenting is justified due to its clinical and laboratory behavior reported in studies relating its elevation after the procedure to a worse late outcome, and due to its low cost.